76fbf0a755
Mobile devices use different monospace fonts (Courier on iOS, Droid Sans Mono on Android) with larger ascent/descent metrics than desktop fonts. With lineHeight: 1.0, calculated cell height was smaller than actual glyph height, causing block characters to render at ~3/4 height. Increasing to 1.2 gives mobile fonts proper vertical space while maintaining desktop compatibility. Quality gates: TypeScript check passed, production build successful